How to auto fetch OTP, if we use multiple text fields

Question

I know that if we want to auto fetch the OTP(if we use single textfield) we need to use

otpTextField.textContentType = .oneTimeCode

But, If

Answer 1

-> From iOS 12 Apple will allow the support to read One Time Code which you will get in the iPhone device. you can split text into four fields and autofilled and manually enter otp and remove one by one and move each textfield.

1) self.textone maxmimum length 4 and other textfield max length 1

2) Add UITextFieldDelegate

if #available(iOS 12.0, *) {
   txtOne.textContentType = .oneTimeCode
}
self.txtOne.addTarget(self, action: #selector(textFieldDidChange(_:)), for: .editingChanged)
self.txtOne.becomeFirstResponder()

  @objc func textFieldDidChange(_ textField: UITextField) {
    if #available(iOS 12.0, *) {
        if textField.textContentType == UITextContentType.oneTimeCode{
            //here split the text to your four text fields
            if let otpCode = textField.text, otpCode.count > 3{
                txtOne.text = String(otpCode[otpCode.index(otpCode.startIndex, offsetBy: 0)])
                txtTwo.text = String(otpCode[otpCode.index(otpCode.startIndex, offsetBy: 1)])
                txtThree.text = String(otpCode[otpCode.index(otpCode.startIndex, offsetBy: 2)])
                txtFour.text = String(otpCode[otpCode.index(otpCode.startIndex, offsetBy: 3)])
            }
        }
     } 
  }

 func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {

       if (string.count == 1){
           if textField == txtOne {
               txtTwo?.becomeFirstResponder()
           }
           if textField == txtTwo {
               txtThree?.becomeFirstResponder()
           }
           if textField == txtThree {
               txtFour?.becomeFirstResponder()
           }
           if textField == txtFour {
               txtFour?.resignFirstResponder()
               textField.text? = string
                //APICall Verify OTP
               //Timer.scheduledTimer(timeInterval: 0.1, target: self, selector: #selector(self.VerifyOTPAPI), userInfo: nil, repeats: false)
           }
           textField.text? = string
           return false
       }else{
           if textField == txtOne {
               txtOne?.becomeFirstResponder()
           }
           if textField == txtTwo {
               txtOne?.becomeFirstResponder()
           }
           if textField == txtThree {
               txtTwo?.becomeFirstResponder()
           }
           if textField == txtFour {
               txtThree?.becomeFirstResponder()
           }
           textField.text? = string
           return false
       }

   }